Re: Help in writing infix macro in CL.

[NGALL@G.BBN.COM]

    Date: Mon,  5 May 86 16:27:46 PDT
    From: "S. Sridhar" <sridhar%tekecs%tektronix.csnet@CSNET-RELAY.ARPA>
    To: common-lisp@su-ai.ARPA
    Subject: Help in writing infix macro in CL.
    Message-ID: <8605052327.AA21173@tekecs.TEK>
    
     
    Is there a way to do the following using the reader macro functions
    of CLtL ?
    
     I want to have a reader macro that translates
     (a + b) to (+ a b). How can I remember the lisp object that was read
     before the macro character #\+.
     
    I would appreciate some pointers.
    
    
    -sridhar
    
	      --------------------
		
As Scott pointed out, there is no way in CL to access what has been
read prior to the execution of a read-macro.  To do what you want, you
would have to redefine the read-macro for #\( to save the elements
seen so far in a list that is manipulatable via a global variable.  A
less ambitious approach might be to use [...] around infix
expressions; then you wouldn't have to worry about breaking (...).

	-- Nick